An air conditioning system for providing cooling and dehumidification of a room space is known in the art as disclosed in Patent Document 1 (WO03/029728 pamphlet). The air conditioning system includes a refrigerant circuit provided with an indoor heat exchanger as a utilization side heat exchanger and an outdoor heat exchanger as a heat-source side heat exchanger and runs a refrigeration cycle by circulating refrigerant through the refrigerant circuit. Further, the air conditioning system dehumidifies the room space by setting the refrigerant evaporation temperature in the indoor heat exchanger below the dew point of the room air and condensing moisture in the room air.
A dehumidifier is also known which includes heat exchangers each provided with an adsorbent on the surface thereof, as disclosed in Patent Document 2 (Published Unexamined Japanese Patent Application No. H07-265649). The dehumidifier includes two heat exchangers (adsorption heat exchangers) each provided with an adsorbent for moisture adsorption thereon and moisture desorption therefrom and operates so that one of the two heat exchangers dehumidifies air and the other is regenerated. During the operation, the adsorption heat exchanger adsorbing moisture is supplied with water cooled by a cooling tower while the heat exchanger being regenerated is supplied with warm water. Further, the dehumidifier supplies the air dehumidified by the above operation into the room space.
—Problems to be Solved—
As described above, the air conditioning system disclosed in Patent Document 1 copes with latent heat load in the room space by setting the refrigerant evaporation temperature in the indoor heat exchanger below the dew point of the room air and condensing moisture in the air. In other words, although indoor sensible heat load can be coped with even if the refrigerant evaporation temperature in the indoor heat exchanger is higher than the dew point of the room air, the refrigerant evaporation temperature is set at the lower value in order to cope with the latent heat load. This provides a large difference between high and low pressures in the refrigeration cycle and raises the input to the compressor, which leads to a problem that only a small COP (Coefficient Of Performance) can be attained.
On the other hand, the dehumidifier disclosed in Patent Document 2 supplies water cooled by the cooling tower, i.e., cooled water having not much lower temperature than the room temperature, to the heat exchanger. Therefore, the dehumidifier has a problem that it can cope with latent heat load but not sensible heat load in the room space.
The present invention has been made in view of the foregoing points and, therefore, its object is to provide an air conditioning system which can cope with both of sensible heat load and latent heat load in the room space and attain a high COP.